<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <style type="text/css">
        div {
            border: 1px solid red;
            padding: 10px;
        }
        /* 只清空li标签样式 */
        li {
            list-style: none;
        }
    </style>
    <title>Document</title>
</head>
<body>
    <div>
        <div>
            <div>
                <div>123</div>
            </div>
        </div>
    </div>
    <div>
        <div>1</div>
        <div>2</div>
    </div>
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
    </ul>
</body>
</html>